Breast cancer is the most commonly diagnosed cancer and the second leading cause of cancer death in women in the United States. The lifetime risk of developing breast cancer has risen dramatically in the past several decades, while overall mortality rates have remained almost static. Despite considerable progress, the understanding of breast cancer, as well as the ability to control it, is still rudimentary. The University of Washington Breast Cancer Database and Biologic Resource Bank research project was formulated with the belief that the battle against breast cancer will be won much more swiftly if we are able to provide clinical and basic science breast cancer researchers with access to adequate clinical databases and biologic tissues. Large volume, well-defined, longitudinal breast cancer clinical databases and corresponding biologic samples are essential in answering important questions about breast cancer etiology, prevention, diagnosis, and treatment and are currently in need of development. The primary aim of this research proposal is to facilitate the development of a national resource of biologic materials linked to a substantial clinical database. Our plan to achieve this goal includes developing a comprehensive clinical database, tumor tissue bank and serum/lymphocyte bank from the population of breast cancer patients at the University of Washington Medical Center. We will explore the feasibility of incorporating a variety of other tissues into such a biologic bank, including immortalized lymphocytes, bone marrow specimens, skin biopsies, lymph node biopsies, metastatic tumor samples, and benign breast tissues. Additionally, we will investigate the feasibility of incorporating other institutions into our linked database and biologic resource bank, with the ultimate goal of participating in a National Biologic Resource Bank. In designing this project, we have aimed to address and protect patient confidentiality and consent, to include representative patients of all ethnicities, ages, and economic status, and to provide equitable access to these resources for all researchers.